How to Clean Fuel Injectors

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How to Clean Fuel Injectors

Believe it or not, most of the common problems that engines have are due to clogging. In fact, car owners often experience clogged fuel injectors when they have been lax in maintenance. Some people opt to get this done professionally, especially when the vehicle is due for a tune-up at the mechanic, and others do not want to wait and prefer to clean the injectors by themselves at home. This saves money on labor. Additionally, clean fuel injectors also save fuel, cut down on emissions, and ensure that the vehicle runs at peak performance. Informed buyers who are serious about making sure that their vehicle runs well should know the step-by-step process of cleaning their fuel injectors. When it comes to troubleshooting its performance, it is also crucial to know the fuel injector's specific role in the engine.

Overview of Fuel Injectors

Before learning how to clean fuel injectors, it is important to define them and their role in the internal combustion cycle. From the name itself, fuel injectors are the devices that "inject" fuel in the fuel-air mixture required for combustion. It atomizes the fuel and turns it into a fine mist by pushing it forcibly through a tiny nozzle in a high-pressure manner. This is sprayed onto the intake valves and into the engine's combustion chamber.

As for the amount of fuel pushed inside the fuel injector, it is determined by the engine control unit (ECU), which monitors the amount of air flowing inside the engine, the oxygen in the exhaust, the throttle valve position, the coolant temperature, the system voltage, the engine speed, and many other things.

Reasons to Clean the Fuel Injector

Clean fuel injectors are necessary for fuel economy and peak engine performance. After a certain number of miles, the fuel injector can get clogged, causing it to misfire or sputter. Leftover gasoline in fuel injector nozzles tend to solidify after the engine is turned off. This is called "heat soak" where the fuel residue from the nozzle evaporates, and a wax-like residue remains. Heat soak occurs during the cooldown process of the vehicle. This is after the car owner drives the vehicle and the engine is fully warmed up and the gasoline residue is baked to a waxy residue on the injector tip. This occurs when the engine is turned off and no air and no fuel flows through the engine to cool it down and wash it away. After some time, this causes a significant buildup that needs to be cleaned so the engine can function properly.

Ideally, injectors should be cleaned every 15,000 to 30,000 miles. Cars with higher mileage, however, need to be cleaned more often. Old vehicles, especially those that have pintle-style multiport injectors are more prone to these types of problems. Injectors that are exposed to more heat are also vulnerable to clogging. The rule of thumb is the hotter the location, the higher the tendency for the injector to clog. Car owners who do not clean their fuel injectors often experience decreased fuel economy and dirty emissions. Since residue piles up over time, it is important to get this done every so often.

Fuel Injection Cleaning

Car owners can get their fuel injectors cleaned by a professional mechanic or do it on their own. These injectors may be flushed with solvents while remaining inside the engine or taken out for more thorough cleaning. One way to know that fuel injectors require cleaning is when the car owner experiences lower gas mileage and power loss. The engine hesitating after pressing the gas pedal could also be a sign that the injector requires cleaning. Fuel injector cleaners are often a mixture of detergents that dissolve and remove the deposits on the injectors. These typically come with manufacturer-specific instructions on how to apply the cleaners. Fuel injector cleaning kits come with the tools necessary to do the job, such as a canister and gauge as well as a hose and fittings, but the required fluid may or may not be sold separately.

Step-by-Step Guide to Cleaning Fuel Injectors

  1. While it is always best to follow the instructions that come with the specific cleaning solution, the following is a general method for applying fuel injection cleaners. This may be useful for those who have lost the directions that came with the cleaner.
  2. First, take out the fuel pump and connect the fuel return line, or insert a U tube so the gas returns to the tank.
  3. Detach the pressure regulator.
  4. Next, hook up the cleaning kit to the fuel port, which is located on the fuel rail.
  5. Take off the gas tank's fuel cap to make sure that pressure from the cleaning kit does not build up in the system.
  6. To ensure that the engine does not turn over, the ignition must be turned. Take extra precautions that the fuel pump is turned off when this is done.
  7. Open the valve on the kit canister until the fuel pressure reads the number that matches that for the vehicle. This should be written in the cleaning kit's instructions. It may also be found in the service manual for the vehicle.
  8. Run the engine so the cleaner goes through the injectors. Stop when the engine turns itself off or all the solvent is used. This normally lasts for five minutes.
  9. Reset the switch for the fuel pump and put the gas cap back on.
  10. Reattach the pressure regulator.
  11. Turn the engine on and verify that the injectors are working properly by listening for rapid clicking sounds, which verify that the engine is working as it should.

DIY Injector Cleaning Limitations

The do-it-yourself approach to cleaning the fuel injectors is not meant for everyone. For those who do not know a lot about vehicles, cleaning their vehicle's injectors by themselves may cause more problems than it solves. The following are some limitations of this approach.

CO and HC levels in emissions must be tested to know if the cleaning worked. Consider doing an injector pressure drop test as well. Fuel cleaners may not work for injectors that are extremely clogged. During the cleaning cycle, the solvent may not properly pass through the injectors. Additional cleaning cycles may be required, or the vehicle may need to be brought to a professional mechanic anyway. Strong detergent solvents may be harmful to the fuel regulator, pump, and lines, especially since most of these are made from plastic and rubber.

When all of these do not work, consider the fact that the injectors may require replacement or more thorough cleaning done using a high-pressure professional machine. Alternatively, mechanics may recommend that the injectors be removed from the engine for more thorough cleaning. They may also recommend that the combustion chambers and intake valves be cleaned along with the fuel injectors. Oil, filter, and spark plugs may also be replaced. When this still does not fix the problem, keep in mind that there are many other reasons why the engine hesitates or why the car has high fuel mileage.

Purchasing Fuel Injection Products on eBay

Those who are shopping for fuel injection products online should start by visiting the eBay homepage. Type the phrase "fuel injection cleaner&" to start a general search. Those who are looking for something specific can also type additional search terms, such as the brand of cleaning fluid, to narrow down the results. You can narrow the results down even further by selecting filters located at the sidebar. These filters only display items in certain categories, price ranges, with certain shipping options, that come from a specific seller location, or are either new or used. Another way of searching is to use eBay's Advanced Search function. This gives you the option to specify your requirements before searching. This means you get a more targeted search from the outset.

Whether you prefer buying from local sellers or looking for a fuel injection cleaner that is only available outside the country, eBay can help in finding these sellers. For those who are looking to save on shipping costs, there are sellers who offer free shipping or local pickup. You may also find that some are authorized sellers of particular fuel cleaners, which is helpful if you wish to only deal with sellers backed by the product's manufacturer.


People who are looking for ways to save money on car repairs and tune-ups should consider cleaning their fuel injectors every 15,000 to 30,000 miles. Doing this on a regular basis can save on expensive car repairs in the future. Having a clean and well-functioning fuel injector also saves money when it comes to fuel economy as well. Fuel injectors are the pieces responsible for turning fuel into a fine mist before it gets sprayed into the combustion chamber. When there is not enough fuel sprayed due to clogged injectors, this can lead to engine problems. This is why cleaning the fuel injectors on a regular basis is important. For the person who is intent on doing the cleaning by themselves, they can purchase fuel injector cleaners from their local car mechanic or online. Fuel injector cleaners are typically made from strong detergents, solvents, and additives that are run through the engine using a high-pressure valve to clean the build-up. When fuel injectors are clean and clear, the engine can work at its peak performance.

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